function xnsslopeFn = nsslopeFn(x)
xnsslopeFn = (-514*sin(x(1) + x(2) + x(3) - x(4)) -  ...
  685*sin(x(1) + x(2) + x(3) - x(4) - x(5)))/ ...
 (514*cos(x(1) + x(2) + x(3) - x(4)) +  ...
  685*cos(x(1) + x(2) + x(3) - x(4) - x(5))) ...
;